studies. In their study, lenalidomide was given when the disease was controlled after a first-line immunochemotherapy [3], while in ours, the maintenance phase was started after eight cycles of the combination of Rituximab-Lenalidomide in relapse or refractory PCNSL patients. In our study [1], the maintenance treatment did not allow an optimal disease control as reflected by the high incidence of relapses in the first months of the maintenance, resulting in a continuous drop in the progression-free survival (PFS) curve. The small benefit of the maintenance shown in our study could result either from the relapse/refractory status of our patients, from acquired tumor resistance to lenalidomide or to the use of a reduced dose of lenalidomide. Indeed, in a previous escalating-dose phase I study, Rubenstein et al. showed that lenalidomide diffused in the CSF when given from 15 mg [4]. The effect of the low-dose lenalidomide in maintenance in the prolonged PFS observed in their patients is indeed suggested by the study by Vu et al. but will need to be confirmed in further studies. We completely agree that the rationale for using low-dose lenalidomide in a maintenance phase as a targeted agent with immunotherapeutic properties is appealing, since we actually based the maintenance phase with low-dose lenalidomide in our REVRI study on this immunologic rational, although robust data supporting this rationale were lacking. Maintenance therapy is indeed an important issue to be addressed in PCNSL, and especially in elderly patients. Prospective studies aiming at evaluating different kinds of maintenance treatment are ongoing by academic groups including ours (NCT02313389, NCT02623010, NCT03495960). In the REVRI trial, we preferentially discussed the use of lenalidomide in combination with immunechemotherapy in the first-line therapy of PCNSL patients to improve complete response rate, rather than further focus on the maintenance phase. We are nevertheless eager to know the results of prospective trials that will evaluate lenalidomide as a maintenance treatment in a larger series of patients including translational immunologic studies.

Aim: Talimogene laherparepvec (T-VEC) is an intralesional therapy for unresectable, metastatic melanoma. T-VEC real-world use in the context of anti-PD1-based therapy requires further characterization. Materials & methods: A retrospective review of T-VEC use from 1 January 2017 and 31 March 2018 for melanoma patients was conducted at seven US institutions. Results: Among 83 patients, three categories of T-VEC and anti-PD-1 therapy were identified: T-VEC used without anti-PD-1 (n = 29, 35%), T-VEC after anti-PD-1-based therapy (n = 22, 27%) and concurrent T-VEC and anti-PD-1-based therapy (n = 32, 39%). 25% of patients discontinued T-VEC therapy due to no remaining injectable lesions, 37% discontinued T-VEC due to progressive disease. Discontinuation of T-VEC did not differ by anti-PD-1-based therapy use or timing. Conclusion: In real-world settings, T-VEC may be used concurrently with or after anti-PD-1-based therapy.